In-Situ Synthesis of Polypyrrole-MnO2−x Nanocomposite Hybrids

This work centers on hybrid materials based on MnO2-x and conducting polymers and their possible application as electrodes in rechargeable lithium batteries. We approached the study of these hybrids as an alternative to crystalline manganese oxides, which capacity is frequently limited by irreversible phase transitions. We followed the approach of forming simultaneously the organic and inorganic components in an attempt to get nanocomposite materials. PPy/MnO2-x nanocomposite hybrids were prepared by direct one-pot reaction of pyrrole and potassium permanganate, obtaining hybrids with different amounts of the inorganic phase. The results on the chemical, spectroscopic and electrochemical characterization of the PPy/MnO2-x hybrids indicated that as the MnO2-x content increases, so does the initial specific charge in lithium rechargeable cells, reaching values as high as 134 Ah/Kg.5Partial financial support from the Ministry of Science and Technology (Spain) (GrantMAT2002-04529-C03) and from CONACYT (México) (fellowship to A.K. Cuentas-Gallegos) are gratefully acknowledged.Peer reviewe

Triple hybrid materials: A novel concept within the field of organic–inorganic hybrids

We explored a new approach within the field of hybrid materials, namely, an integration of an electroactive inorganic molecule into a conducting polymer that in turn is intercalated into an extended inorganic oxide. In particular we present the specific material formed by hexacyanoferrate-doped polypyrrole or polyaniline inserted in turn into layered V2O5. This novel kind of hybrid with three components interacting at a molecular level is what we have called, triple hybrid materials (THM). The synthetic approach was based on our earlier work on PAni/V2O5, PAni/HCF and PPy/HCF systems. The materials obtained were characterized by FTIR, XRD, TGA, elemental analyses, and ICP. The electrochemical properties of THMs as insertion cathodes in rechargeable Li cells were also explored. The initial specific charge was high for PPy/HCF/V2O5 system (160 Ah kg−1), giving a greater value than for their corresponding simple hybrids: PPy/HCF (69 Ah kg−1) and PPy/V2O5 (120 Ah kg−1). Repeated charge–discharge cycles showed a poor cyclability, which could be related to the voltage limit values during recharge, overoxidation of the polymer, or to the detrimental effect of structural water from THMs. Nevertheless, the present work showed a novel route towards a more complex and versatile electroactive hybrid design.Partial financial support from the Ministry of Science and Technology (Spain) (Grant MAT2002-04529-C03) and from CONACYT (México) (fellowship to A.K. Cuentas-Gallegos) are gratefully acknowledged.Peer reviewe

Hybrid Materials Based on Vanadyl Phosphate and Conducting Polymers as Cathodes in Rechargeable Lithium Batteries

[ES]: El fosfato de vanadilo es bien conocido como una fase inorgánica laminar capaz de intercalar una gran variedad de moléculas orgánicas. Mediante la polimerización in-situ, de anilina o pirrol, en la fase inorgánica es posible preparar materiales híbridos orgánico-inorgánicos en los que el polímero queda intercalado. Se describe la síntesis y caracterización de este tipo de híbridos y algunos resultados preliminares de su aplicación como materiales activos de cátodo en celdas reversibles de litio.[EN]: Vanadyl phosphate is a well known layered inorganic phase, capable of intercalating a great variety of organic molecules. By means of an in-situ polymerisation of aniline or pyrrole between the layers of the inorganic phase, it is possible to obtain organic-inorganic hybrids. We describe the synthesis and characterization of these type of hybrids, and some preliminary results of their application as active cathodic materials for positive electrodes in reversible lithium cells.Agradecemos la financiación de este trabajo a través de los proyectos MAT2001-709-C04-01 y MAT2002-04529-C03, y al Consejo Nacional de Ciencia y Tecnología de México (CONACYT) por la concesión de una beca predoctoral a A.K Cuentas-Gallegos.Peer reviewe

Study of Hybrid Cathode Materials and Vitreous Anodes. Characterization in Lithium Ion Cells

[ES]: Como parte de nuestros estudios de nuevos materiales de electrodos para aplicación en celdas reversibles de litio, hemos abordado el estudio de materiales vítreos e híbridos [1] como posibles alternativas a los materiales activos cristalinos, que ven frecuentemente limitada su capacidad como resultado de transiciones de fase irreversibles. Dentro de este trabajo se presentan aquí los resultados recientes sobre cátodos híbridos de PPi/MnO2 (PPi= polipirrol) y de PAni/V2O5 (PAni= polianilina), y de ánodos basados en vidrios en el sistema V-Ni-Te-O, así como de su combinación en celdas reversibles de ion litio. Hemos logrado obtener mediante reacción directa de pirrol con permanganato el híbrido PPi/MnO2, y hemos observado que en la síntesis de PAni/V2O5 existen factores que influyen positivamente en su comportamiento electroquímico.[EN]: This paper is based on new materials applied as electrodes in rechargeable lithium batteries. We have approached the study of glassy and hybrid materials as an alternative to crystalline active materials, which capacity is frequently limited by irreversible phase transitions. We present here our latest results on hybrid cathodes, PPy/MnO2 (PPy= PPi= polypirrol) and PAni/V2O5 (PAni= polyaniline), and anodes based on glasses of V-Ni-Te-O, and their combination in reversible lithium ion batteries. We have obtained the PPy/MnO2 hybrid by direct one-pot reaction of pyrrole and permanganate, and for the preparation of PAni/V2O5 we have determined the positive influence of some parameters on the electrochemical behaviour.Peer reviewe

Materiales híbridos basados en fosfato de vanadilo y polímeros conductores como cátodos en baterías reversibles de litio

Vanadyl phosphate is a well known layered inorganic phase, capable of intercalating a great variety of organic molecules. By means of an in-situ polymerisation of aniline or pyrrole between the layers of the inorganic phase, it is possible to obtain organic-inorganic hybrids. We describe the synthesis and characterization of these type of hybrids, and some preliminary results of their application as active cathodic materials for positive electrodes in reversible lithium cells.<br><br>El fosfato de vanadilo es bien conocido como una fase inorgánica laminar capaz de intercalar una gran variedad de moléculas orgánicas. Mediante la polimerización in-situ, de anilina o pirrol, en la fase inorgánica es posible preparar materiales híbridos orgánico-inorgánicos en los que el polímero queda intercalado. Se describe la síntesis y caracterización de este tipo de híbridos y algunos resultados preliminares de su aplicación como materiales activos de cátodo en celdas reversibles de litio

Electrochemical supercapacitors based on novel hybrid materials made of carbon nanotubes and polyoxometalates

We have characterized symmetric solid-state supercapacitors in swagelok cells using film electrodes made of novel hybrid materials based on multiwalled carbon nanotubes (CNT) and phosphomolybdate polyanion (Cs-PMo12) with PVA as binder. These hybrid materials were carried out by Cs-PMo12 adhesion onto previously functionalized CNT, in order to disperse both components at a molecular level and use Cs-PMo12 as energy density enhancer in supercapacitor cells. Our results show high capacitance values (up to 285 F/g at I = 200 mA/g) due to the contribution of Cs-PMo12, which was revealed on the higher energy density values compared to pure CNT electrodes. Additionally, good stability was observed during 500 charge–discharge cycles for most hybrid electrodes. These preliminary results show a new approach to enhance energy density of double layer supercapacitor cells through the introduction of Cs-PMo12, whereas from a material science point of view these materials are innovative, and open the way to search for diverse applications aside from supercapacitors (sensors, catalysts, photovoltaic cells, etc.)UNAM-MEXICO, Projects IN111106-3 and CVA06000004Peer reviewe